This invention relates to a method for applying an image to a wax article. The invention also relates to wax articles, in particular candles, produced by the method.
It has long been known to apply images to candles. In particular candles sold for special occasions (either public festivals such as religious festivals, or private celebrations such as weddings) may bear images commemorating that occasion.
One method of applying such an image to a candle is to form the image on paper or similar material, and mount the material bearing the image to the candle. However, as paper is more combustible than wax, the paper catches fire when the candle burns, and the image on the paper is burnt away or rendered unrecognizable long before the candle is burnt out. Moreover, as paper does not adhere well of its own accord to wax, it would be necessary to use adhesive, staples or other such material to mount the paper etc. To the candle: this adds an extra step which may be difficult to automate, and an adhesive may interfere with the burning of the candle.
GB 1466550 and U.S. Pat. No. 4,030,959 suggest a solution to this problem, by providing a method of transferring images to wax candles, comprising imprinting the image onto a waxed transfer sheet by conventional gravure or lithographic techniques, and then wrapping the imprinted sheet around the candle body while applying heat and pressure thereto.
JP-A-8-197899 discloses two processes for printing candles. One method involves forming a printed image on the release surface of a release sheet expressed with thermal copying toner without thermal fixing (for example, by using a thermal copying machine wherein the heating and pressurising roller has been removed, or by removal of the printed image from the copying machine before it reaches the heating and pressurising roller). The printed image is then adhered to the surface of the candle by the application of pressure. The sheet is then released and the printed image then heated to fuse the toner and soften the surface of the candle. This is stated to allow the toner to fuse on the surface of the candle in a uniform manner.
Another method disclosed by JP-A-8-197899 involves forming a printed image on the release surface of a release sheet expressed with thermal copying toner, heating the surface of the sheet bearing printed image without the application of pressure in order to fuse the toner, adhering the printed image to the surface of the candle, removing the release sheet, and coating the printed image on the surface of the candle with paraffin.
JP-A-2-33397 discloses a transfer paper consisting of a release paper, a printed image-bearing layer and an adhesive layer comprising an adhesive agent which includes rice wax or candela wax having a melting point between 60° C. And 100° C. The document further discloses a method for decorating candles, in which the transfer paper is cut to a predetermined size and is then inserted into a could so that the printed image-bearing layer faces inwards. Molten paraffin wax is then cast into the could, which is then allowed to cool so that the paraffin wax solidifies and the image is transferred to the candle. The release paper is then removed to produce the finished candle.
DE-A1-19649545, DE-U-29623315 and UP-B-941161, all to Bubeck, describe an alternative process for forming color printed images on wax articles and the like, comprising the steps:    a) forming a reverse copy of the desired image on wax-coated transfer paper by means of a color photocopier;    b) fixing the copy to the article; and    c) pressing the copy on to the article by means of suitably shaped tools.
However, a number of problems exist with the method described in the Bubeck documents. A specially shaped tool, corresponding exactly to the shape and size of the required wax article, is required to transfer the image to the surface of the wax article (eg a cylindrical tool for a candle). If the mould is not exact, the image transfer will not be performed cleanly. Temperatures of 60 to 200° C. And pressures of up to 30 bar are required to effect the transfer, and expensive, complex equipment is therefore required. It is also necessary to fix the transfer sheet to an exact location on the wax article before applying pressure: this requires an additional step of forming locating or marking holes or the like in the article. Furthermore, it is necessary to cut the transfer sheet bearing the image to shape before fixing it to the wax article. In addition, in the process described in the above documents, good adhesion of the wax-coated transfer paper to the wax article requires the surfaces of both to be smooth: adhesion is unsatisfactory when either the wax article or the transfer paper has a rough surface. Moreover, as the Bubeck process requires the use of a white wax sheet, production of color images on candles is rendered difficult.
In addition, the quality of the image produced by this method is unsatisfactory: the image may peel off the wax surface, particularly at low temperatures. A protective coating of wax or lacquer is required to protect the material. Finally, due to the complexity and cost of setting up the equipment to carry out this method, it is suitable only for production of large numbers of candles etc., production of smaller numbers of candles (eg. for private celebrations) being uneconomic.